what size do you recommend for 167cm?
going to build a bike for my girlfriend. She is currently riding a gravel bike with almost mtb-like geo (long TT, tall HT, short stem) so it's impossible to compare the fit

Sorry I don't get the point.. do you have an integrated cable routing or "classic" style with cable and hoses entering the frame on the top of the bottom tube?

The firespider store at Aliexpress has OD2 cockpits, different styles.. fully integrated also.

 OD2 is your key word for searching at Aliexpress, it gives much better results than 31.8mm or 1 1/4"
Canyon does have 1 1/4" Cockpits, but expensive ..i guess you have a Canyon? There are not so many bike companies with 1 1/4"

I have scott addict. It has fully integrated cables but it's not a 1 piece cockpit but a separate stem and handlebar. Cables however are not routed through the handlebar and stem internally but enter the spacer stack under the stem and I quite like this design since you can remove the stem easily when packing the bike into a box and it's much easier to install. So I was wondering whether there are 1 piece cockpits that allow you to route the cable this way rather than through the handlebars. I know most carbon cockpits will allow you to run either full integration or completely external cables that are not routed through the headset